Yes Stu, as far as I can tell the house bank is 2 batts in parallel each side of the 3-pos switch below the fuse panel. The boat came to me (2nd owner) that way and I assume it was as built. Since the reserve (single engine start batt) has its own switch next to the batt in the cockpit locker, I am inclined to leave it that way.It appears that you have a split house bank, and use the switch to put them together. Why bother?
Wire them together for the largest house bank and use that same switch to control your reserve bank.